Isopropanol → 6-ethyl-9-oxo-9H-indeno[1,2-b]pyrazine-2,3-dicarbonitrile

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Reaction Conditions

Reaction Steps

A suspension of 29c (298 mg, 1.71 mmol) and diaminomaleonitrile (185 mg, 1.71 mmol) in iPrOH (17 ml) was stirred at 80° C. for 20 h. The solvent was evaporated under reduced pressure and the crude was purified by flash chromatography (CH2Cl2). The obtained product was purified by preparative HPLC, obtaining 32 as yellow solid as 7:3 regioisomeric mixture with the 7-ethyl analogue. 1H NMR (300 MHz, CDCl3): main product: δ 7.95 (d, 1H), 7.80 (m, 1H), 7.67 (bd, 1H), 2.83 (q, 2H), 1.33 (t, 3H); minority product: δ 7.89 (d, 1H), 7.89 (m, 1H), 7.56 (bd, 1H), 2.86 (q, 2H), 1.36 (t, 3H). ESI+MS: calcd for C15H8N4O: 260.26; found: 261.1 (MH+).

Provenance & Evidence